青刺果ACE抑制肽的分离纯化、结构鉴定及其体外活性评价

Isolation,Identification,Structure Characterization and in Vitro Activity Evaluation of ACE Inhibitory Peptides from Prinsepia utilis

以具有血管紧张素转化酶(ACE)抑制活性的青刺果蛋白酶解物为研究对象,采用超滤、强阴离子交换层析分离纯化ACE抑制肽,液相色谱-串联质谱鉴定其肽序列。采用傅里叶红外光谱、酶反应抑制剂动力学、MTT试验和分子对接技术解析其二级结构特征、体外活性以及与ACE的结合机制。结果表明,分子质量<3 ku的超滤组分活性较好(IC50=0.380 mg/mL),离子交换层析后以F-a组分活性最好(IC50=0.159 mg/mL)。质谱鉴定出4条肽序列,通过生物信息学分析确定肽PGDVF为潜在的ACE抑制肽[IC50=(0.56±0.1)mmol/L]。二级结构分析表明PGDVF由α-螺旋(20.28%)、β-折叠(6.21%)、β-转角(31.55%)和无规则卷曲(41.85%)构成,其抑制模型为非竞争性抑制,肽质量浓度小于1 mg/mL时,对HepG2细胞无毒性。分子对接显示PGDVF可通过氢键、疏水作用与ACE紧密结合,从而有效抑制ACE活性。研究结果可为青刺果降压肽的开发利用提供参考。

In this study,ACE inhibitory peptides were isolated and purified by ultrafiltration and strong anion exchange chromatography,and their peptide sequences were identified by LC-MS/MS.Fourier transform infrared spectroscopy,enzyme reaction inhibitor kinetics,MTT assay and molecular docking technology were used to analyze the secondary structure characteristics,in vitro activity and binding mechanism with ACE.The results showed that the activity of<3 ku ultrafiltration fraction was better(IC50 value:0.380 mg/mL),and the activity of F-a fraction was the best(IC50 value:0.159 mg/mL)after ion exchange chromatography.Four peptide sequences were identified by LC-MS/MS,and bioinformatics analysis further confirmed that the peptide PGDVF was a potential ACE inhibitory peptide with an IC50 value of(0.56±0.1)mmol/L.the secondary structure analysis showed that PGDVF was composed ofα-helix,β-sheet,β-turn and random coil,and its inhibition model may be mixed.The peptide concentration less than 1 mg/mL was basically non-toxic to HepG-2 cells.Molecular docking showed that PGDVF could be closely combined with ACE enzyme through hydrogen bond and hydrophobic force,thus effectively inhibiting ACE activity.In summary,this study can provide reference for the development and utilization of Prinsepia utilis decompression peptide.